Secondary clock system



Feb. 3, 1942. J. w. BRYCE 2,271,539

SECONDARY CLOCK SYSTEM Filed DeC. l, 1959 9 SheeiZs--Shee'tl 1 Sdn/manyclark sica/MARY crac/r FIGA.

MISTER 6206/( INVENTOR www ATTQRNEY Feb. 3, 1942. J, w, BRYcE SECONDARYcLocx SYSTEM l, 1959 9 Sheets-Sheet 2 Filed Dec,

lNVENTOR ffm ,fd/4m ATTORNEYS Feb. 3, 1942.

J. w. BRYCE 2,271,539

SECONDARY CLOCK SYSTEM Filed Deo. 1, 1959 9 sheets-sheet s FIGS.

Feb. 3, 1942.

J. W. BRYCE SECONDARY CLOCK SYSTEM Filed Dec. 1, 1959 9 sheets-sheet 4/Mw/If. @a

INVENTOR W MAX/MUM A856 [55A a' lBY ATTORNEY 5 Feb. 3, 1942. J. w. BRYCE2,271,539

SECONDARY CLOCK SYSTEM Filed Deo. 1, 1939 9 Sheets-Sheet 5 SECONDARYCLOCK SYSTEM Filed Dec. l, 1959 9 Sheets-Sheet 6 INVENTOR Feb. 3, 1942;J. w. BRYCE 2,271,539

SECONDARY CLOCK SYSTEM Filed DeC. l, 1959 9 Sheets-Sheet '7 INVENTORH6141. ZV

ATTORNEY .5

Feb 3, 1942- J. w. BRYCE 2,271,539

SECONDARY CLOCK SYSTEM Filed Deo. 1, 1939 9v Sheets-Sheet 8 INVENTOFlam. www

ATTORNEY 5 Feb. 3, 19472,. J. w. BRYCE 2,271,539

SECONDARY CLOCK SYSTEM Filed Dec. 1, 1939 9 Sheets-Shea#l 9 FIGS.

nam nam new' F1644.:

Flauw.` ff L INVEN-ro ATTORNEY 5 Patented Feb. 3, 1942 2.271.539SECONDARY CLocx SYSTEM James W. Bryce, Glen Ridge, N. J., assignor to AInternational Business Machines C orporation,

New York, N. Y., a `corporation of New York Application member 1, 1939,seran No. 301,027

(c1. sis- 24) 9Clalms.

This invention has for its object the provision of an improved clocksystem including a master clock and one or more secondary clocks,wherein the secondary clocks are of improved form.

In general the invention has for its objects the provision of clocksystems wherein the secondary clocks are always kept synchronized withthe master clock without the use of any special synchronizing controls.Each secondary clock instantly changes from one time indication to thenext and gives a visible indication which is visible both in the day andnight time with separate illumination. The system is of such nature thatthe time is displayed at the secondaries by numerical characters and thecharacters may be of any desired size.

A further object of the present invention resides in the provision of anovel clock system which utilizes cathode tubes forvthe secondary clockunits. Such tubes are adapted to visually display time and use verylittle current so that very small conductors may be employed.

A further object resides in the provision of suitable controls at amaster clock for controlling the cathode ray secondary clocks so thatthey will all show the time of the master clock and change from one timeindication to another.

A further object of the present invention resides in the provision oi aclock system wherein a. secondary clock may be connected to the supplylines and immediately show the time transmitted from the master clockwithout any manual initial setting of the secondary clock.

A further object of the present invention resides in the provision of asystem wherein diiferent times such as Eastern Standard time andGreenwich time may be optionally derived from a clock or clocks of thesystem without mental calculation.

A further object of the present invention resides in the provision of aclock system wherein the secondary clocks are simple, inexpensive, quickin operation, dustproof and weatherproof and so constructed that nomoving parts are required therein.

An incidental object resides in the provision of novel program operatedcontrols to cut the clocks out of circuit or in circuit at desiredtimes. For example, the clocks may be on only during working hours tothereby save current and prolong the working life of the clocks andapparatus of the system.

Further and othencbjects of the present invention will be hereinafterset forth in the accompanying specification and claims and shown in thedrawings which show by way of illustration a preferred embodiment andthe principle thereof and what I now consider to be the best mode inwhich I have contemplated oi! applying that principle. Other embodimentsof the invention employing the same or equivalent principle may be usedand structural changes made as desired by those skilled in the artwithout departing from the present invention and within the spirit ofthe appended claims.

In the drawings:

Figure 1 isvan isometric view of a complete system:

Fig. 2 is a fragmentary detail view of the master clock;

Fig. 3 is an elevational viewof a steppin switch; f

Fig. 4 is a sectional view taken on line I-l of Fig. 3;

Fig. 5 is a top plan view of the pattern component emitter unit, withportions of a cover broken away to show the parts beneath;

Fig. 6 is a detail sectional view taken online 6-6 of Fig. 5 and lookingin the direction of the arrows;

Fig. 7 is an elevational detail view taken on line 1-1 of Fig. 6;

Fig. 8 is a detail view of a pattern component emit-ter disk. Theparticular disk illustrated is the one for affording the components torepresent the digit '7:A

Fig. 9 is a diagrammatic graph view showing the digit 7 .with variousplotting points delineated thereon;

Fig. 10 shows layouts of the other pattern component emitter disks fordigits 1 to 6 and 8 through 0 inclusive;

Figs. 11 to 13 are views of pattern component emitter disks for thenumbers 10, 1l and 12 respectively;

Figs. 14a, 14h, 14c and 14d, taken together and arranged horizontallyfrom left to right in the manner delineated in Fig. 15 show a completecircuit wiring diagram; y .v

Fig. 15 is a diagrammatic view showing the relation of the circuitsheets .in Figs. 14a, 14h, l4c and 14d.

Heretofore secondary clock systems controlled from master clocks haveusually been of the impulse type and such systems have usually includedsynchronizing devices to keep the secondary clocks in synchronism withthe master.

clock. Furthermore, impulse operated secondaries have been comparativelynoisy in operation.

The present invention is directed to the provision of a novel clocksystem which includes secondary clocks of novel type. The secondaryclocks are of such type that the use of synchronizing devices may bewholly obviated since the general nature of the system is such that thesecondary clocks always display the time shown by the master clock. Thesecondary clocks further are an'inertialess type and are absolutelysilent. The master clock is of conventional form but each secondaryclock unit comprises three cathode ray tubes and provision is made forcontrolling these cathode ray tubes from the master clock so that thetubes show hours and minutes of time throughout the day. In place ofusing the conventional clock dials the 'time is displayed by eachsecondary clock in numbers, i. e. railroad time, for example, a quarterof four will be shown as 3:45. The secondary clocks are luminous andaccordingly the time may be seen day or night. Control of the display ofnumbers by the secondary clock is secured by applying proper varyingvoltages to the defiecting plates of the cathode ray tubes. Suchcontrolling defiecting volt ages are generated by a 4set of patterncomponent emitter devices which are disposed at the master clock. Thereare a plurality of such pattern component emitters one for each of thedigits from 1 through 0 and one for each of the numbers 10, 11 and 12.The master clock'controls stepping switches, which connect the properpattern component emitters to the secondary clocks so that they willdisplay figures representative of hours and minutes.

The system is also adopted for displaying time according to EuropeanContinental practice, that is to say, two oclocl; p, m. could be shownas 1li.

General layout of system Relerring to Fig. l, 20 generally designatesthe master clock unit which has the customary pro gram unit. 2| is thepattern component emitter and ampliiier unit. The stepping switch unitwhich is controlled from the master clock unit is generally designated22. 23 represents secondary clocks. In the drawings only two of suchsecondary clock units are shown, but it is obviously noted that thesystem can include any number of secondary clocks. The secondary clocksmay be connected by plugs to suitable cables which extend to thestepping switch unit and the stepping switch unit is cahled to thepattern component emitter unit and also is connected by cables to themaster clock unit.

Master clock Referring to Fig. 2, the master clock may be of anysuitable type. The master clock herein shown is of the type shown inUnited States patent to Bryce, No. 1,687,481. The master clock inaddition to having the usual minute contacts 24 and hour contacts 25 isprovided with a set of contacts 26 which close every ten minutes. Thesecontacts are cam operated in the customary way and the cam is gearedback to the hour shaft to make one revolution every ten minutes.

The master clock may also include a program unit which may be of thetype shown in United States patents to Geiger, No. 1,791,927, andLarrabee, No. 1,680,742.

The program device includes the usual calendar wheels 200 and hourlyprogram disks 20|. 'I'he calendar wheels in conjunction with the programdisks are adapted to close program contacts generally designated 202 onFig. 1. On the f tacts may be used .2 l 2. Closure 0I circuit diagram(Fig. 14k) such contacts are individually designated 202e and 2Mb. Theseconto turn on and oif 'current supply i'or the system at selected timesthrough the use oi' the usual make and break relay 204 (Fig. 14h). Eachactuation of this relay under control ci contacts 202g. or 2Mb willshift contacts 202:1 causes closure ofV 2I2 and closure of 2021) causesopening of 2|2.

General characteristics of cathode ray Lubcs Before describing thedetails of the system, the general characteristics of the cathode raytubes which are used in the secondary clocks may be briefly described. Atypical and suitable cathode ray tube is illustrated diagrammatically onthe circuit diagram (Fig. 14e) Such atube com prises an evacuated bodyinto which extends a heater element 2l. Associated with the heaterelement is a cathode 28 providing a source of electrons. Also within theevacuated body and disposed in order from left to right is a grid 29, ananode number "1 designated 3D. an anode number 2 designated 3| and twopairs of deiiector plates. The upper and lower vertical deilector platesare respectively designated YU and YL and the horizontal deilectorplates are designated .XL and XR. XL signiiies horizontal defiection tothe left and XR horizontal deflection of the right. The right hand endof the cathode ray tube includes the .usual fluorescent screened end 32.The Y deilector plates are plates above and below the center axis of thetube. The "X" deflector plates are disposed. to the right and-left ofthecenter axis of the tube.

In the operation of the cathode ray tube, if no potential is applied toeither set of plates the stream of electrons will be emitted along thecentral axis of the tube and impinge on the fluorescent screen 32 at thecenter of the screen.A

This will illuminate a spot at the center of the tube. 1f, however, thepotential on the horizontal and vertical deflecting plates is changed.the stream of electrons can be deflected either upwardly or downwardlyor to the right or the left or in combined resultant directions.Changing relative potential on the Y set of plates will bring the streamof electrons up or down and similarly changing the relative potential onthe X plates will divert the stream of electrons alternatively to theright or left. By providing proper potential and proper changingpotential over a period of time on both sets of plates any desiredfigure or character can be traced on the :fluorescent screen 32. Byrepeatedly tracing the beam of electrons to the proper points or areasof the screen, an image may be produced which can be visibly read in theday time or at night. Cathode ray tubes are adapted to operate anddeilect electron beams at an exceedingly high frequency. They mayaccordingly be termed inertia free image tracing devices.

Having generally described the characteristics of a cathode ray tube,there will now be described one manner of providing the deiiectorvoltages which control the movements of the tracing of the electronicbeam of the various tubes.

(see Figs. 1 and 5) includes a driving motor 33 which by any suitabledrive such as by the belt and pulley arrangement shown is adapted toconstantly rotate a pair oi' shafts ,34.

Fixed at intervals along these shafts 34 area series, of pattern disks,one of which is designated 35 in Figs. 5, 6 and '1. For a clock systemof the type hereinl shown, thirteen disks 35 are required. Each disk Ilis generally opaque but is provided with two transparent tracks (seeFig. 7). One track is designated 35X and the other track is designated35Y. For each disk 35 there is provided two sources of light. -Eachsource of light preferably comprises a lamp 36 within a lamp box 31together with a suitable set of lenses 38. An apertured diaphragm 39 isprovided to direct and concentrate the light received from the lightsource on to and through the transparent tracks of the disk 35. Onelight source directs light to and through the 35X track and the otherlight source directs light through the 35Y track. On the opposite sideof each disk from the lightv source there are provided two photo-cellswhich are respectively designated 40X and 40Y.

If the width of one of the at different angular positions around disk35, different amounts of light will be allowed to pass to the photo-cell40X upon rotation of the disk. This variable illumination will vary theoutput of the circuit controlled by the particular photocell. Thephoto-cells act to allow more or less current to flow in their relatedcircuits depending upon the amount of light which they receive.

The manner of laying out the disks will now be explained. Referring toFigs. 8 and 9, on Fig.

9 the outlines of the numeral '7 have been laid out. -As here shown, thenumeral '7 has vbeen divided into a set of sections of edual length,this particular character being divided into sec- -tions 1- to 31inclusive.

In order to trace the electron beam for the upper horizontal part of thegure '[,the Y component voltage should be maintained constant whilepoints 1 to 13 are traced. If the disk of Fig. 8 be examined andthe 35Ytrack be traced from 1 to 13, it will be noted that the amiss.distancebetweenthe Y axis and point 19 multiplied by anotherconstant.vThis constant I is the ratio of the predetermined arbitrary maxitracks35X is varied I transparent track has a constant maximum' width from allpoints from 1 to 13, thereafter the tracing beam should be caused toboth descend and move to the left. To cause descent of the beam there isa gradual diminution of the width of the Y track from pointv 13 back topoint 31. Referring now to the 35X track, the X component at point 1 is0. From this point 1 to point 13, the X track gradually 1ncreas'es inwidth as indicated on the disk. From point 13 back to point 30 theXtrack progressively diminishes in width.

To determine the width of the Y track at any point as for example point19,'the Y ordinate distance between the X axis and point 19 in a drawingof the character such as Fig. 9 is determined, this distancel is thenmultiplied by a constant, the value of which is determined in a mannerto be described. The resulting amount mum width of the Xtrack withrespect to the maximum. abscissa value for the character in Fig. 9..This arbitrary value again depends upon the circuit relations andcharacteristics of the X amplifier circuit. In this case the constantsused were identical, but such requirement is not essential. I

Fig. 10 shows the configuration of the tracks which are used for digitsfrom l through 6 inclusiveand tthrough 0 inclusive. Figs. 1i. i2 and 13show the track configurations for controlling the display of numbers 10,lland l2 respectively.

It may be explained for these particular disks that if l a numbercontaining two characters is to be traced, one digit is traced beforethe other digit is traced. The disks, however, rotate at such a ratethat both digits are concurrently displayed. The various disks of Figs.8, 10, 11 to 13 inclusive constitute what may be termed patterncomponent emitters and if these disks are maintained in a state ofrotation at relatively high speed it will be appreciated that they willprogressively vary the X coordinate component voltages and the Ycoordinate component voltages which are applied to the deflecting platesof the cathode ray tubes.

It may be further explained that a common set of pattern componentemitters are utilized for controlling the cathode ray tubes of all thesecondary clocks irrespective of the number oi clocks employed in thesystem and the number of tubes in each clock.

Stepping switch mechanism In order to variably connect the cathode raytubes of the secondary clocks to the pattern component emitter unit asthe time changes, suitable switching mechanism is provided controlled byand from the master clock.A While various forms of switching devices maybe used, Figs. 3 and 4 show a suitable switching mechanism. 4i is asuitable mounting plate which has mounted on it an insulating segment42. Segment 42 is provided with metallic conducting pieces 43 which aredistributed around the periphery. A common conducting segment 44 is alsomounted on plate 4| and insulated from it.` Plate 4i has secured to it astud 45 (see Fig. 4). Rotatable'on the stud 45 is a sleeve 46 which hasfast to it a ratchet 41. Secured to the ratchet by a suitable rivet 48are two wiper arms 49. These wiper arms are disposed between insulatingpieces 50 and the wiper arms are also insulated from the sleeve 46 inthe manner shown in Fig. 4. As the ratchet 41 is rotated /from oneposition to the next, the wiper arms 49 will provide a circuit from thecommon segment 44 successively to each of the individual segments 43. Inorder to rotate the ratchets step by step there is provided a magnet 5iwhich, upon energization, is adapted to move an armature 52 to the rightas shown in Fig. 3. Upon de-energization of the magnet, the armaturereturns to the left under the action of the spring 53, thereby rotatingthe ratchet 41 `one step in a clockwise direction. Retrograde Thevarious segments are connected to various sections of the patterncomponent emitter and Photo-cell and amplifier circuits As explainedbefore, two photo-cells are provided for each digitV or number whoseimage is to be traced. Such photo-cells are in turn con trolled by thedisks heretofore described.

Amplifier circuits preferably including electron discharge devices arecontrolled by the photo cells 40X, MY, etc. These amplifier circuits areadapted to produce variations in potential across the deiiecting platesof the cathode ray tubes in accordance with variations of lightimpressed on the photo-cells.

Referring, for example, to the photo-cell which is utilized to controlnection of the cathode ray beam in a cathode ray tube such as 6i, forsetting up the digit The photocell is connected in series with a hattery 62 and a resistor 63, whereby the difference of potential acrossthe resistor varies in accin'dml ance with the illumination of the photoThe grid cathode circuit oi' e tube conveniently biased negative battery65, includes a portion preliminary adjustable by a com resistor. Theplate cathode circuit ci 'the tube 5I includes a B battery' or othersource ci' direct current 6T and a resistor titl in series therewitl'lintermediate the positive side ci? batte f and the plate of the tubeEil. For infimes. a proper voltage across the horizontal o lectir platesXL and XR oi the cathode tubes L which are connected to the terminalsund of the amplifier unit, a biasing .i'ietworlt ls conu venientlyprovided, .including resistor li con nected across a source of voltagepreferably com prising the series connected batteries l2, it. Theconductor intermediate the batteries 12, it is also connected to apreliminarily adjustable contact N on the resistor 5E and the terminalst9, i are respectively connected to a preliminarily adjustable Contact lon the resistor il and to the positive side of the battery El (i. e. thepositive end of the resistor 68).

It will now be seen that if the photo-cell 40X receives no illuminationoi' a predetermined minimum illumination, the grid the tube Bt will havea predetermined maximum negative bias. The Contact arms B6, 'M and 'i5are con veniently so adjusted (in a manner which will be readilyunderstood by those familiar with the art) that for this 0 orpredetermined minimum illumination of the cell 40X the resulting maximumnegative bias on the grid oi' the tube 64 will be such that the outputvoltage between the terminals 89 and 'i0 will maintain the electron beamat one side of its horizontal path of travel` viz., the left-hand sidein the apparatus illustrated. That is, although the contact arm i4 isnegative with respect to the positive side of the battery 61, thebiasing network including the resistor 'H imposes suiiicient opposingvoltage in the circuit of the deiiector plates XL, XR, as to make theterminal 69 just sumciently positive with respect to the terminal tomaintain the electron beam in its extreme left-hand position. Now, asthe illumination of cell X in- WX, the horizontal de dit creases, thenegative bias on the grid of the tube il decreases, resulting in anincrease of plate current and a corresponding increase of the potentialdrop between the positive side of the battery 61 andthe contact 14. As aresult, the potential of terminal 69 becomes less positive with respectto the terminal 10; the adjustments 'of the contacts on the resistorsbeing convenlently such that the potential between the terminal 69 andi0 becomes zero for an illumination of the photocell 40X which isintended to represent a positioning of the cathode beam at the middle ofits horizontal path. Increase of the illumination beyond this pointresults in making the terminal iD positive with respect to the terminalB9, until at the point of maximum illumination, the cathode beam isdeflected to its extreme right-hand position.

It will be understood that the amplifier and balancing circuitscontrolled by the photo-cell 40Y are conveniently identical with thoseherein above described for the cell MX so that the vertical displacementof the cathode beam between plates YL and YU is obtained by acorrespondingly similar variation of output potential between theterminals "i5, ".17, to which these plates are connected.

Since it will now be 'understood that the actual position of the cathoderay beam at any instant depends upon the controlling potentials orvarying coordinate electrical components applied to both sets otdeilectiug plates KL, and YL, YU, the ,position oi the beam is directlycontrolled (through the instrumentality of the amplifier cir cuitsdescribed) by the amount oi illumination respectively received by thephoto-cells 40X, till?.` 'l'.lhus, iluminatioo respectively recei ed bythese photowells vari 1uring rotation of the pattern component cmi thecathode y beam. traces a path. to portray the particular l t character(in this caso the character il represented by the particular patterncomponent emitter which controls the illumination of the photo-cells,that the tracks 353K and 35Y rcspcctively provide a predeterminedvariation in the illumination of the photo-cells WX and MY for eachcycle of rotation oi the emitter and the resultant of the correspondingvariations in deilecting potentials or varying coordinate electricalcomponents on the plates of the cathode ray tubes, causes the cathoderay beam to trace a path-dn this case e. path depicting the charactor l,which is predetermined by the pattern component emitter.

is shown in Fig. Si, it will be noted that the left hand cathode raytube of each secondary clock is larger than lthe other tubes to theright. This larger left hand tube is provided to distinguish the hourindications from the minute indications. It is accordingly, necessary toprovide auxiliary output circuits in the amplifier units to tracecharacters oi' larger size. This will now be described.

Referring to Fig. i4@ it will be noted that there is a supplemental arm14a picking off the voltage variation acrss the load resistor 68. 'iliais connected into a network 12a, 13a, 1 ia, etc. The arm 15a connectsthe network to an extra output post or terminal 69a. It will beappreciated that the arm '14a' picks off a greater potential than thearm 14 and this greater potential will provide a greater deectingvoltage for the cathode ray tube which is used for displaying largefigures. The biasing network otherwise functions in the mannerpreviously described.

The foregoing description has explained in d tail one section of theamplifier unit with its connections to the photo-cells and to the outputterminals of the amplifier for the ligure 1. It will be understood thatthe amplifier is arranged with a plurality of sections of 'identicalconstruction and wiring. There are such additional sections forcharacters 0, 2 through 9 inclusive, 10, 11 and 12. Such sections areindicated by correspondingly numbered boxes on Fig. 14a of the wlringdiagram.

As shown on Fig. 14h, the amps as' and the motor 33 .may receive currentfrom a source 210 through a switch 2li and such current supply may beunder the control of the program controlled contacts 212.

It will be appreciated that suitable current supply and proper circuitsfor the heater elements of the amplifier tubes 64V and for the heatersof the cathode ray tubes 6| should be provided. Current supply for suchheater elements may be provided by a transformer 2I3. The primary ofthis transformer is controlled by the program contacts 212. Thesecondary of the transformer is connected to lines 2I4 which-lead to theheater elements 0f the amplifier tubes 84 (see Fig. 14a). Other lines215 lead through suitablev cables to the heater elements of the cathoderay tubes 6I of the various secondary clocks and to the heater elements`of the amplifier tubes |06 in the various secondary clocks. Suchamplifier tubes |06 will be hereinafter described in greater detail.

When the clock system is inuse and at proper times, suitable currentsupply is provided by the' program devices, for the cathode ray tubes6I-f and for the amplifier tubes 64. The cathoderay tubes 6| are at thevarious secondary clocks and the amp-liner tubes 64 are at the masterclock.

Circuit diagram Before describing the details of operation of thecircuit diagram of the system it may be rst generally explained thatthere are two stepping switches provided for minute control. These areso labeled on Fig. 14h. The next two switches below are the switches forcontrolling tens of minutes and lare so labeled and the bottom fourstepping switches are for hour control. In connection with the hourcontrol it may be mentioned that with the present system provision ismade for obtaining a supplemental time reading for Greenwich Mean timeat a secondary clock, that is to say, if the secondary clocks showEastern Standard time for example, by pushing a button on a particularsecondary clock, Greenwich Mean time or some other time may be shown atthat clock.

Switches designated 43a-44a and 43h-44h vcontrol the Y and X deflectingvoltages respeccells which analyze the X track of the 0, 1, 2-9 patterncomponent emitter disks. The individual segments 43c of switch 43c-44care connected to the related output terminals 16 of the amplifier unitsfor the 40Y photo-cells which analyze the Y track of the 0, 1, 2-5pattern component emitter disks. The segments 43d of switch 43d- 44d areconnected to the related output terminals 69 of the amplifier units forthe 40X photo-cells which analyze the X track of the 0, 1, 2-5 patterncomponent emitter disks.

The individual segments 43e of the switches 43e-'44e are connected tothe related output terminals I16a of the amplifier units for the 40Yphoto-cells which analyze the Y track of the 1, 2-9, V10, 11 and 12pattern component emitter disks. The individual segments 43f of switches43f-,44f are respectively connected to the output terminals 69d of theamplier units for the`40X photo-cells which analyze the X track of the1, 2-9, 10, 11 and 12 pattern component emitter disks.

As explained-before, provision is made to enable a clock or clocks todisplay Greenwich Mean time as well as Eastern Standard time forexample. To provide for such alternative reading of a particular clock,supplemental switches are provided. For this purpose the followingswitches and wiring are provided. Wired in parallel with the segments43e and 43j are the segments 43g and 43h respectively of switches43g-44g and 43h-44h. The switch arms 49g and 49h are disposed five stepsin advance of the arms 49e and 49j to thereby aiiord a control for thecathode ray tubes BIH to'indicate thereon the hours for Greenwich meantime whichv is five hours spectively of the cathode ray'tubes 61H (Hdesignating hours).

The individual segments 43a of switch 43a-44a are connected to theoutput posts 16 of the amplifier unit for the 40Y photo-cells whichanalyze the Y track of the 0, 1, 2-9 pattern component emitter disks.The individual segments 43h of switch 43h-44h are connected to theoutput terminals 69 of the amplifiers for the 40X photoahead of EasternStandard time.

To explain further, if Eastern Standard time is to be read' at asecondary clock, the control is derived from the switch arms 49e and49j. If Greenwich mean time is to be read at a secondary clock, thecontrol is derived from the switch arms 49g and 49h.

, The foregoing description has traced the circuit relations between theamplifier terminals and the stepping switches, and more particularly tothe segments to the stepping switches. The

circuits from the common strips of the stepping switches to thesecondary clocks will now be explained.

Referring to Fig. 14h, common segment 44a I is connected to a circuitleading to the YL plates of the cathode ray tubes 61M of all thesecondary clocks. Likewise common segment 44h is connected to the XLplates of the tubes 61M in all the secondary clocks.

In practice it will be understood that a common set of wires in a cablewill extend to the various secondary clocks and all of the clocks willbe connected in multiples to the wires in, such cable. In practice eachsecondary clock may have its variousA circuit connections extended to aplug such as 205 (see Fig. l) which can be inserted in a receptacle 206which is suitably connected to the wires within the cable generallydesignated 201 in Fig. 1. The cable 201 also includes the wires 2 l5previously referred to which supply current to heaters of the amplifierand cathode ray tubes of the secondary clocks.

Referring now to Fig. 14h of the circuit diagram, 24 are the masterclock control contacts which close once a minute.. Thesecontacts uponclosure, energize a motor magnet 5IM. 51M upon successive energization.advances the arms of the minute stepping switches. Contacts 26 are themaster clock control contacts which close every ten minutes to energizemotor magnet EIT. These magnets in turn effect the advance of thestepping switch arms 9c and 49d which pertain to tens of minutescontrol. Contacts 25 are the master clock control contacts which closeonce an hour to energize stepping switch magnets BIH and SIHG. SII-Iadvances the stepping switch arms 49e and |91 pertaining to hours andstepping switch magnet IHG advances the advanced stepping switch arms49g and 49h which control Greenwich Mean time indications.

Greenwich Mean time control Referring to Fig. 1, it will be noted thatone of the secondary clocks, i. e. the one to the right, is shown with asupplemental button 80. While this supplemental button is shown on oneclock only, it is obvious that it can be provided on all of the clocksif it is so desired. Depression of 90 on any clock provided with thisfeature shifts contacts 80a and 80h (Fig. 14o) so that the circuits tothe Y and X deflecting plates of the hours cathode ray tube BIH arederived from the common segments Mg and 44h instead of from the regularsegments e and 44j. This gives an advanced indication of the hour timereading at the particular secondary clock where the sup plemental buttonis depressed.

Circuit and operation The complete circuit will now be traced fordisplaying a time indication at a particular clock. Assume the masterclock shows ten hours and forty-four minutes. With this condition of themaster clock, the switch arms 49e and 49)' will be resting on the 10number segments 43e and 43j respectively. Circuits will be completedtraced as follows: From output terminal 69a of the 10 amplier unit, line8|. segment spot number i0 of the 43! group, arm 49f, common segments"f, wire 92 in cable 201, through the plug and via wire 82a (Fig. 14o)to contacts 80h in the position shown and through Wiring 83 to the XLplate BIH. Also at this time the 10 terminal of the 10" amplifier unitis connected to a common line 94 (Fig. 14a) which extends va wire 85 inthe cable 201, through the plug and through wire 95a in the secondaryclock, to the XR, plate of tube BIH. Accordingly, the changing potentialvariations between terminals SSa and 10 will eiIect proper horizontaldeection of the beam of the cathode ray tube to properly trace thehorizontal component voltages for tracing the two digit number 10. Forcontrolling the vertical deilecting potentials on the Y plates, thefollowing circuits are established. From terminal post 19a o! the 10ampliiier unit, a circuit is established from wire 81 (Fig. 14a) to the10 segment spot of the 43e group (Fig. 14h) thence through arm 49e,common segment 44e, wire 88 in the cable 201, through the plug and wire88a (Fig. 14e) in the secondary clock, through contacts 90a in theposition shown, wire 89 to the YL plate of tube BIH. The YU plate isconnected to wire 95a which by the circuit previously traced is extendedto terminal post 11 of the "10 ampliiler unit. Accordingly, thepotential variations between posts 16a and 11 are applied respectivelyto the YU and YL plates of tubes BIH. With such X and Y change ofpotentials applied to the plates of this tube BIH from the 10 ampliiierunit, the number 10 will be traced on the screen of the cathode ray tube6 IH.

In order to display forty-tour minutes on the tens and units tubes, thefollowing circuits are established. From the 69 terminal of ampliiierunit 4," a wire 9| (Fig. 14a) leads to the 4th segment spot of segments43o (Fig. 14h) and the 4th segment spot of segment group 43d. Fromterminal 1E of the "4 amplifier unit a wire 92 leads to the 4th segmentspot of segment 43a and to the ith segment spot of segment 43e. At thistime switch arm 49d is standing on the 4 segment spot. Accordingly, acircuit is completed from this switch arm to strip Md, thence via wire93 in the cable 201, through the plug, wire 93a in the secondary clockto the XL plate of tube HT. The XR plate of this tube is connected to awire 94 which extends back via lines 85a and to the 10 terminal of the4" amplifier unit. At the same time switch arm 49e is standing on the 4segment spot of the 43e group and a circuit is completed through 44o,via a wire 95 in cable 201, through the plug wire 95a. in the secondaryclock, to the YL plate of tube 61T. The YU plate is connected to theline 94 which through the circuit previously traced connects back toterminal 11 of the 4" amplifier unit.

The circuits just described provide for the tracing of the gure 4 by thetens cathode ray tube EIT. Switch arm 49h is now standing on the 4segment spot of the set of segments 43D. Accordingly, a circuit iscompleted through MIJ, Wire 91 in. the cable 201, through the plug,through wire 91a in the clock, to the XL plate of tube SIM. 'I'he XRplate of this tube .is connected via wire 98, wire 85a, wire 85, back tothe 10 terminal of the "4 amplifier unit. Switch arm 49a is alsostanding on the 4 segment spot position of the set of segments 43a andaccordingly a circuit is completed through Ma, via wire 99 in the cable,through the plug, wire 98a in the secondary clock, to the YL plate oftube EIM. The YU plate of this tube is connected to line 98 and backthrough the circuits previously traced to the 11 terminal of amplifierunit 4. These circuits will provide the proper potentials for tracingthe figure 4 by minutes cathode ray tube SIM.

The foregoing tracing of circuits has traced the circuit connectionsfrom the amplifier units for tracing ten hours and fortydour minutes.When the master clock advances to the next minute, the minute contacts24 close and advance the minutes stepping switch arms 49a and 49h fromthe 4th spot to the 5th segment spot. This operation of the steppingswitches will cut oi the 4 amplifier unit and 4 pattern componentemitter disk from circuit and will establish a circuit to the 5amplifier unit and 5 pattern component emitter disk. Accordingly, 5 willthen be displayed by the units of minutes too. The operation need not betraced for further time indications as it is similar to that previouslyexplained.

It will be appreciated that the operation of the secondaries is whollynoiseless and that with this particular system synchronizing devices arenot necessary since the various secondary clocks al ways receive at anygiven instant the voltage potentials proper to trace the time asdirected by the master clock.

It will be noted that each cathode ray tube is provided with the usualbiasing battery I0 I, one end of which is connected to the cathode 28,the other end being connected to the common line leading t0 YU and XRplates. An adjustable tip |02 also applies suitable potential to thepoint.

number 1 anode designated 30. This is a customary cathode ray tubecircuit.

Suppression of return trace The electron beam of the electric cathoderay tube in tracing a number will proceed from one point to the nextpoint and then to the terminating point and then quickly return to thestarting With such quick return occasionally a faint trace may be seenon the screen on the tube as the beam jumps from the last point to thefirst point of a number. Referring to Fig. 9, for example, in tracingthe number 7, the beam goes from points 1 to .13, then downwardly topoint 31 and .then quickly jumps back as shown in the dotted line topoint l. Also in tracing the numbers 10, 11 and 12, the beam in jumpingfrom the 1 to the 0 in 10, and the 1 to the 1 in 11, or the 1 to the 2in 12, would show a faint trace. The return trace, so to speak, occursat a relatively high frequency and this high frequency characteristicsis used to wholly suppress the cathode ray beam on passing from theterminating point of one iigure to the beginning point of that ligure orof another figure.

Referring to the disk shown in Fig. 8, the Y track at the point 1. whichalso corresponds to the point 31, has a sudden increase in width. Suchsudden increase of width of track will increase the current iiow throughtube 64 (Fig.

14a) thereby increasing the potential across the resistor 68. l

Referring to Fig. 14o there is shown a. resistor |03 in series with twocondensers |04 and |05. This assembly of resistors and condensers isdisposed intermediate circuit 99a and circuit 98 on the GIM tube forexample. When the track of a pattern component emitter abruptly changesin width, there is a rapid change of potential applied to the twocondensers |04 and |05. By properly proportioning the condensers theresistor |03 will receive current only upon such rapid change ofpotential. With such current ow across resistor |03, the upper end ofthe resistor will increase in potential with respect to the lower end ofthe resistor, thereby decreasing the normal bias on a supplemental tube|06. Such normal bias is supplied by a suitable battery |01. Increasedcurrent ilow in the plate circuit of tube |06 will accordingly increasethe potential drop across a resistor |08 and thus apply an increasenegative bias to the grid 20 of the cathode ray tube. This increasednegative bias applied to the control grid will momentarily suppress thecathode ray tracing beam and will continue the suppression until point 1has been again reached. Grid 29 receives its normal bias through anorma1 biasing battery |09 disposed in the circuit relation shown.

The system has been explained incorporating the program unit. By the useofthe program unit, the current supply for the various heating lamentsand lamps and for the driving motor may be turned oi during non-workinghours to conserve current and length of life of the various lamps andtubes. However, such program control may be dispensed with if desired.With a clock system of the type described wherein the secondary clocksare of the cathode ray type, it is possible to connect a clock to a lineat any point in the system, and this secondary clock without any manualsetting whatsoever will immediately display the time indication of themaster clock. No setting of a particular clock has to be made and nospecial-synchronizing controls are necessary.

What is claimed is: l

1. The invention according to claim 5 wherein a plurality of cathode raytubes are provided for displaying a plurality of time indicating digits.

2. The invention according to claim 5 wherein a plurality of cathode raytubes are provided for displaying a plurality of indication digits, oneof said tubes displaying a multi-digit time indication, and wherein thepattern control means of the source means includes supplemental patterncontrol source means providing electrical coordinate components for therequired multi-digit character display.

3. A clock system with a master clock and one or more secondary clocks,with channels between the master and the secondary clock or clocks,including in combination, generating means including continuouslymovable pattern control source means for all of the different digits forgenerating the different trace controlling coordinate componentsrequired for controlling the tracing of the outline of each of all ofthe different digits which may be displayed by the secondary clock orclocks, each secondary clock including cathoderay tube means havingcharacter tracing and displaying means associated therewith andresponsive to said generated electrical trace controlling coordinatecomponents, switching mechanism controlled by the master clock forselectively rendering the pattern control source means related to thetime position of the master clock effective through said channels tocontrol tracing of the related digit or digits by a cathode raysecondary clock or clocks whereby the secondary clock or clocks maydisplay time related to master clock time.

4. A clock system with a master clock and one or more secondary clockswith lines leading from the master clock to the secondary clock orclocks and including in combination, generating means including patterncomponent source means for the different digits for generatingelectrical trace controlling coordinate components for controlling thetraclngs of outline of each of the digit or digits to be displayed bythe secondary clock or clocks, each secondary clock comprising cathoderay tube means having associated therewith character displaying andtracing means responsive to said generated trace controlling coordinateelectrical components, diiferent sets of switching mechanisms controlledby the master clock for connecting the generating means related to thetime position of the master clock to the said lines whereby a secondaryclock may display a time related to the master clock time, and meansat asecondary clock for selectively connecting said clock to diierent setsof lines which carry electrical trace controlling coordinate componentspertaining to diierent times from said different sets of switchingmechanisms at the master clock, one set of said switching mechanismsbeing in phase with the time indication of the master clock and theother switching means being displaced in phase with respect to the timeindication of the master clock.

5. In a clock system comprising a. master clock and one or moresecondary clocks, the combination wherein the secondary clocks includecathode ray tubes for displaying time indications, generating means atthe master clock, including pattern control source means, one for eachdifferent digit or character to be displayed by the secondary clock orclocks, for generating the diiferent electrical trace controllingcoordinate components required for tracing the outline of each of thediierent characters which are required for representing time indicationsat the secondary I clocks, with means under control of the master clockto control the display and change of display of time indications bythe'cathode ray tubes of the secondary clock or clocks, said last namedmeans including means for selectively causing the electrical tracecontrolling components corresponding to the master clock timeasgenerated by the generating means under control of the related patterncontrol source means to control the cathode ray tube or tubes of thesecondary clock or clocks to trace the outline of the related digit ordigits and display the master clock time.

6. In a clock system with a master clock and one or more secondaryvcloclrs With electrical channels between ,the master clock and thesecondary clock or clocks. the Acombination of generating meansincluding source means for coordinate pattern components for each one ofdifferent digits to, be displayed by the secondary clock, means forphoto-electrically sensing the source means for the coordinate'patterncomponents, mechanism for continuously moving the source means andsensing means relatively to each other to cause the generatingmeans togen'- erate recurrently the electrical coordinate componentscorresponding to the different' .coordinate pattern components for thedigits-'which may be displayed, circuits controlled by the .generatingmeans for transmitting through sai-d channels the electrical coordinatecomponents of.:

the digits to be displayed, said secondary clock comprising a cathoderay tube -with digit tracing and display means associated therewith andresponsive to the electrical coordinate components transmitted throughsaid channels, and switching means selectively controlled by the masterclock according to master clock time for selecting the electricalcoordinate components for effectively controlling the digit tracing anddis- 1 Adifferent digits or characters to be displayed and ponents ofthe generated set.

varying electrical coordinate components required for controlling thetracing of the outlines of a set of all the different time indicationswhich may be displayed at different times by the secondary clock orclocks, said generating means including continuously movable controlmeans and switching mechanism controlled by the master clock inaccordance with master clock time for selecting from the set ofgenerated components those components corresponding to time indicationsrelated to master clock time for effectively infiuencing the cathode raytube means of the secondary clock or clocks so that the latter displaytime indications relate to master clock time.

9. In a clock system comprising a master clock and one or more secondaryclocks, the combination wherein the secondary clocks include cathode raytube means adapted to receive electrical coordinate components forcontrolling the tracing and visible display of time indications,generating means associated with the master clock for generating the setof varying electrical coordinate components required for controlling thetracing of the outlines of a set of characters which comprises all ofthe different time indications which possibly may be displayed atdifferent times by the secondary clock or clocks, with means under thecontrol of the master clock to control the display and change of displayof time indications by the cathode ray tube means of the secondary clockor clocks, said last named means including switching means to select, inaccordance with master clock time, which electrical coordinatecomponents of the complete set of generated components are to beeilective to cause visible display of the indications by the cathode raytube means and to reject unwanted com- JAMES W. BRYCE.

CERTIFICATE or CORRECTION. Patent No. 2,271,559. February 5, 191m.

JAMES w. BRICE.

It is hereby certified that error appears in the printed specificationo'f-'the above. numbered patent requiring correction as follows g' Page7, :gecond column., line 22, claim, after "different" insert e1ectrica1;and that the said LettersPatent should be read with this correctiontherein that the Same may conform to the record of the 'case in thePatent ffice.

Signed and sealed this 21st day of April, A. D. 19142.

Henry Van Aredale, (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION. Patent No. 2,271,559. February 5, 1914.2.

JAMES W. BRYCE.

It is hereby certified that error appears in the printed specificationofthe above* number edpatent requiring correction as follows z' Page 7,second column; line 22', claim 5, after different insert --electrical;and that the said Letters-Patent should be read with this correctiontherein that the same may conform to the record of the 'case in thePatent office.

Signed and sealed this 21st dey of April, A. D. 19h-2.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

